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Full-Text Articles in Developmental Neuroscience

Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang Oct 2015

Developmental Decline In Neuronal Regeneration By The Progressive Change Of Two Intrinsic Timers, Yan Zou, Hui Chiu, Anna Zinovyeva, Victor Ambros, Chiou-Fen Chuang, Chieh Chang

Victor R. Ambros

Like mammalian neurons, Caenorhabditis elegans neurons lose axon regeneration ability as they age, but it is not known why. Here, we report that let-7 contributes to a developmental decline in anterior ventral microtubule (AVM) axon regeneration. In older AVM axons, let-7 inhibits regeneration by down-regulating LIN-41, an important AVM axon regeneration-promoting factor. Whereas let-7 inhibits lin-41 expression in older neurons through the lin-41 3' untranslated region, lin-41 inhibits let-7 expression in younger neurons through Argonaute ALG-1. This reciprocal inhibition ensures that axon regeneration is inhibited only in older neurons. These findings show that a let-7-lin-41 regulatory circuit, which was previously …

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Effects Of Polychlorinated Biphenyl (Pcb) On Response Perseveration And Ultrasonic Vocalization Emission In Rat During Development, Howard Cromwell Dec 2013

Effects Of Polychlorinated Biphenyl (Pcb) On Response Perseveration And Ultrasonic Vocalization Emission In Rat During Development, Howard Cromwell

Howard Casey Cromwell

The 3 major symptoms of autistic spectrum disorders include 1) social behavioral alterations, 2) problems in communication and 3) higher-order motoric deficits of perseveration and stereotyped movements. Previous work has shown that early developmental exposure to polychlorinated biphenyls (PCBs) alters rat pup social motivation and juvenile rat social recognition/investigation. The present work extends this previous research by examining how perinatal PCB exposure alters motoric functions and communication abilities at different stages of development. Action perseveration was examined using performance measures from a T-maze environment. Communication abilities were evaluated by monitoring ultrasound emission in rat pups during a brief isolation from …

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Pleiotropic And Isoform-Specific Functions For Pitx2 In Superior Colliculus And Hypothalamic Neuronal Development, Mindy Waite Dec 2012

Pleiotropic And Isoform-Specific Functions For Pitx2 In Superior Colliculus And Hypothalamic Neuronal Development, Mindy Waite

Mindy Waite

Transcriptional regulation of gene expression during development is critical for proper neuronal differentiation and migration. Alternative splicing and differential isoform expression have been demonstrated for most mammalian genes, but their specific contributions to gene function are not well understood. In mice, the transcription factor gene Pitx2 is expressed as three different isoforms (PITX2A, PITX2B, and PITX2C) which have unique amino termini and common DNA binding homeodomains and carboxyl termini. The specific roles of these isoforms in neuronal development are not known. Here we report the onset of Pitx2ab and Pitx2c isoform-specific expression by E9.5 in the developing mouse brain. Using …

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A Novel Taulacz Allele Reveals A Requirement For Pitx2 In Formation Of The Mammillothalamic Tract, Mindy Waite Dec 2011

A Novel Taulacz Allele Reveals A Requirement For Pitx2 In Formation Of The Mammillothalamic Tract, Mindy Waite

Mindy Waite

The hypothalamic mammillary region is critical for spatial memory and vestibular processing. Pitx2 encodes a paired-like transcription factor that is highly expressed in the developing mammillary region and is required for subthalamic nucleus formation. Here we analyzed a loss of function Pitx2-TaulacZ knock-in allele to study the effects of Pitx2 deficiency on neuronal projections in the embryonic mammillary region. Pitx2-expressing neurons contribute axons to principal mammillary, mammillotegmental and mammillotectal tracts. Embryos with Pitx2 deficiency exhibit axonal fibers in the principal mammillary tract that are improperly bundled and disorganized, yet project caudally toward the tectum and tegmentum. Embryos …

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Distinct Populations Of Gabaergic Neurons In Mouse Rhombomere 1 Express But Do Not Require The Homeodomain Transcription Factor Pitx2, Mindy Waite Dec 2011

Distinct Populations Of Gabaergic Neurons In Mouse Rhombomere 1 Express But Do Not Require The Homeodomain Transcription Factor Pitx2, Mindy Waite

Mindy Waite

Hindbrain rhombomere 1 (r1) is located caudal to the isthmus, a critical organizer region, and rostral to rhombomere 2 in the developing mouse brain. Dorsal r1 gives rise to the cerebellum, locus coeruleus, and several brainstem nuclei, whereas cells from ventral r1 contribute to the trochlear and trigeminal nuclei as well as serotonergic and GABAergic neurons of the dorsal raphe. Recent studies have identified several molecular events controlling dorsal r1 development. In contrast, very little is known about ventral r1 gene expression and the genetic mechanisms regulating its formation. Neurons with distinct neurotransmitter phenotypes have been identified in ventral r1 …

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Gabaergic And Glutamatergic Identities Of Developing Midbrain Pitx2 Neurons, Mindy Waite Jan 2011

Gabaergic And Glutamatergic Identities Of Developing Midbrain Pitx2 Neurons, Mindy Waite

Mindy Waite

Pitx2, a paired-like homeodomain transcription factor, is expressed in post-mitotic neurons within highly restricted domains of the embryonic mouse brain. Previous reports identified critical roles for PITX2 in histogenesis of the hypothalamus and midbrain, but the cellular identities of PITX2-positive neurons in these regions were not fully explored. This study characterizes Pitx2 expression with respect to midbrain transcription factor and neurotransmitter phenotypes in mid-to-late mouse gestation. In the dorsal midbrain, we identified Pitx2-positive neurons in the stratum griseum intermedium (SGI) as GABAergic and observed a requirement for PITX2 in GABAergic differentiation. We also identified two Pitx2-positive neuronal populations in the …

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Autism-Like Behavioral Phenotypes In Btbr Ttf/J Mice. Genes, Hewlet Mcfarlane Dec 2007

Autism-Like Behavioral Phenotypes In Btbr Ttf/J Mice. Genes, Hewlet Mcfarlane

Hewlet McFarlane

No abstract provided.

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The Effects Of Prenatal Stress On Motivation In The Rat Pup, Howard Cromwell Dec 2007

The Effects Of Prenatal Stress On Motivation In The Rat Pup, Howard Cromwell

Howard Casey Cromwell

Exposure to prenatal stress (PNS) has been shown to induce a set of psychological and behavioral changes in developing offspring. We used the rodent model to investigate whether PNS produces changes in the ability of the pup to express social motivation.We used a set of behavioral tasks including monitoring ultrasonic vocalizations after isolation, a conditioned place preference, and a novel and familiar odor approach test. Pregnant Long–Evans rats were exposed to an unpredictable, variable stressor twice daily during the third week of gestation. Isolation vocalizations were assessed on postnatal day (PND) 10. Pup affinity for the dam was evaluated on …

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